In the semi-automatic welding and repair welding of such articles as gas turbine engine alloy components, it is a general practice to add filler material in the form of metal wire, ribbon, etc., which is fed mechanically into a molten weld puddle or pool. As used herein, the term "wire" is intended to include such other equivalent material forms. Such a pool can be provided as a result of an electric arc generated between an electrode and a work surface of the workpiece, a plasma arc or other such heating torch means. Relative motion is provided between such electrode and the work surface to enable the arc or torch to traverse that portion of the surface to be welded or repaired.
In many welding applications, the wire has been seen to melt prematurely before it can reach the region of the weld pool and arc, thus causing an accumulation, such as a drop or globule, to form on the end of the wire. This accumulation enlarges and, when it finally reaches the electric arc/weld pool region, results in uneven deposits of filler material. One suggested remedy has been to extend the feed nozzle through which the wire of filler material is fed to provide more chill to the wire. Other suggestions have included reducing the diameter of the wire, or increasing the feed, or sliding the wire along the work surface to provide more chill to the wire through such surface. Such methods have been found to be only partially successful, and undesirable.